The dual purpose of this application is to request support for the training of G. Steven Bova M.D. as a medical scientist, and to advance understanding of the molecular events leading to the development of prostate Cancer. Dr. Bova seeks to build upon his background as pathologist and urologic surgeon to become an independent investigator in the basic science of urologic oncology. This research training would take place under the sponsorship of William B. Isaacs Ph.D., in the setting of the Brady Urologic Institute of The Johns Hopkins University School of Medicine. Despite the magnitude of the medical problem which prostate cancer constitutes, a basic understanding of the molecular events responsible for the initiation and progression of this disease remains elusive. The primary research goal of Dr. Isaacs' laboratory is to identify and clone the genes which, as a result of genetic alteration, are responsible for human prostate carcinogenesis. To this end, a systematic approach utilizing molecular and cell biology techniques has been initiated to analyze molecular genetic aspects of human prostate cancer. Preliminary studies by Dr. Bova and others have demonstrated frequent loss of genetic material from chromosomes 8p, 10, 16q, and 17p, suggesting that genes important in the development of prostate cancer are located in these regions. Specific aim 1 is to test the hypothesis that tumor suppressor genes reside in these deleted chromosomal regions by introducing normal chromosomes 8, 10, 16, 17 and others into human prostate cancer cells via microcell transfer. Tumorigenicity of hybrid cells will be assayed by injection in nude mice. Motility and invasive potential of hybrid cells will be assayed by time-lapse videomicroscopy, complemented by in vitro assays of extracellular matrix invasion. The presence and degree of intactness of transferred chromosomes will be determined by a combination of molecular and cytogenetic techniques, including Southern blotting, PCR analysis, and in situ hybridization. Specific aim 2 is to provide a base for positional cloning efforts by identifying subchromosomal regions capable of suppressing the tumorigenic phenotype by comparing the effect of transfer of intact and partially deleted chromosomes into wild type cells. These studies will provide the first functional evidence for the existence and location of tumor suppressor genes which become inactivated in human prostate cancer.